![Southern Living Summer Squash Skillet in the skillet ready to serve](https://cdn.statically.io/img/www.southernliving.com/thmb/8OSXzvBzTbnXpydEaXWL9ciIIMs=/1500x0/filters:no_upscale():max_bytes(150000):strip_icc()/27589_BTY_Zucchini_06-1-549deabd035344b187a1ca523cef883b.jpg)
Greg Dupree; Food Stylist: Chelsea Zimmer; Prop Stylist: Prissy Montiel
I love a good cheesy and creamy squash casserole as much as the next person, but more often than not, I’m craving something that highlights the seasonal produce a bit more. With fewer ingredients and a little less dairy, this lightened-up take on a squash casserole is the dish I keep coming back to all summer long. It’s simple, easy, and comes together in just your cast-iron skillet.
It’s also a great way to use up all that farm-fresh squash and zucchini that is in abundance throughout the season. The Gruyère that’s folded into the veggies gives it the traditional casserole-creaminess, while the panko breadcrumbs and extra cheese sprinkled on top result in a nice crispy layer.
Ingredients
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2 Tbsp. olive oil
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2 large (12 oz. each) zucchini, cut into 1/4-in.-thick slices (about 5 1/2 cups)
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1 large (12 oz.) yellow squash, cut into 1/4-in.-thick slices (about 2 1/2 cups)
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1 medium-size (8 oz.) yellow onion, thinly sliced (about 2 cups)
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1 tsp. kosher salt, plus more to taste
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1/2 tsp. black pepper
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1/4 tsp. crushed red pepper
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7 oz. Gruyère cheese, shredded (about 1 3/4 cups), divided
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1/3 cup panko (Japanese-style breadcrumbs)
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1 tsp. grated lemon zest (from 1 lemon)
Directions
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Preheat oven to 400℉. Heat oil in a 12-inch cast-iron skillet over medium-high. Add zucchini, squash, onion, salt, and black pepper. Cook, covered, stirring occasionally, until squash mixture is mostly tender, about 10 minutes. Uncover and cook over medium-high, stirring occasionally, until tender and most of the liquid has evaporated, about 5 minutes.
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Remove from heat, and fold in crushed red pepper and 1 cup of the Gruyère. Stir together panko, lemon zest, and remaining 3/4 cup Gruyère in a small bowl; sprinkle evenly over squash mixture. Bake in preheated oven until golden on top, about 18 minutes.